Having had the opportunity to own both these vehicles (both 2000 models), I feel it pertinent to pen some thoughts on comparing the two.
Some may argue that this would be like comparing apples to oranges, and to a certain extent they would be correct. However, as they both represent two-seater, sports car options, I think it appropriate to articulate the pros and cons of each.
The most important comparison we must make in order to take the rest of this review in context is the list price of each - $36,900 for the Z3 vs. $25,055 for the Miata SE - an almost $12,000 dollar difference. It is important to point this out first, as the main focus of any comparison between these two vehicles must answer the question - are those $12,000 really worth it?
I am also obliged to point out that this $12,000 comparison is conservative, considering the fact that few BMW's go for much below list price, while Mazda is more eager to "deal". Also, an additional $2,000 are needed for the Z3 to gain the leather seats, wood console, CD player and other amenities the Mazda SE offers.
Perhaps a comparison with the Z3 2.3 would be more appropriate, since it comes with a $31,300 MSRP. The additional $2500 needed to bring the Z3 to a comparable level of features with the Miata SE keeps the difference in the $10,000+ level. However, since I did not OWN a 2.3, I owned a 2.8, I cannot make a fair comparison. My actual price difference was $17K.
Delving into these price details is irrelevant. Again, is it worth it? $17,000? $12,000? $10,000?
My answer? It depends. :)
I'm sorry for the wishy-washy answer, but it really does depend! Let me explain.
The Miata SE is a 140 horse powered 4 cylinder "cute little car". The 2.8 is a 193 horse power, 6 cylinder roadster. You definitely get more power in a Z3, no questions about that. The question is, do you really need it?
Why do you want a roadster? If your intent is to race the car and you need the extra power, then by all means go for it. But I find myself shifting from third gear to sixth (the Mazda SE has a six-gear tranny) all too often as I reach the legal speed limit in very short order.
The Z3 is a very beautiful car, with excellent looking curves and ageless design. The Miata, although not as aggressive, holds its own in the "looksy" department. Both are two seaters, both are convertibles, and both have little miniscule trunks.
The Miata SE sound system (for those of us who care) rides as many circles around the Z3 Harmon Kardon system as the Z3 engine runs around the Miata engine. Turnabout is fair game here. The Miata's Bose system outperforms the Z3 with the top up and down, hands up and down. The comparison isn't even fair. For almost $40,000, you would expect a better sound system. If you expect it, you will be disappointed.
The Miata SE air conditioner is also much superior to the Z3. The cabin cools of much sooner, even in very hot weather. To me, these little details add (or detract) from my driving enjoyment.
The Z3 has larger wheels (my model had the 17" cross spoke wheels) and a power top option (for more $$$). The Miata LS, one step down from the SE, has leather and a five speed tranny, and does not come with the wood appointments the SE has, such as a wood steering wheel, wood console, gear shift and emergency brake. You can get some wood appointments on the Z3 for extra dollars, but no wood wheel.
The RIDE? How is the RIDE?
As you would expect, the Z3 rides like a dream. Acceleration is strong, handling is superb, and it remains true to the BMW heritage.
But the Miata is no slouch. Although a much smaller engine, it feels very competent and strong. I must confess I have as much fun driving my Miata SE as I did my Z3.
And isn't that the point?
Why do you want a roadster?
If your intent is to have a second car to play with, ride topless on cool autumn nights and "play", the Miata is an excellent toy. If you can afford the extra $10K-$17K, then go for a Z3.
However, if you are like most of us and must stay within a budget, you will not be disappointed with a Miata. If you are in an even greater budget you can forego the leather and other niceties and deal a base Miata for $19K. You can buy two of these Miatas for what it will cost you to own a fully loaded Z3 2.8.
Is it worth it?
You be the judge. Test drive both cars and tell me that one is worth a couple hundred dollars a month more than the other. In my case, I'd rather spend the money somewhere else, and have almost as much fun with my Miata 2000 SE.
But that's just my humble opinion, of course. :)